Refrigerating apparatus



Jam. .13, 19331. F. E. STEVENSON REFRIGERATING APPARATUS Filed Nov. 3, 3,926

attozwag Patented Jan. 13, 1931 1 NHTED STATES maria FRANCIS E. STEVENSON, 0F DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO FRIGIDAIRE CORPORATIQN, A CORPORATION OF DELAWARE REFRIGERATING- APPARATUS Application filed November 3, 1926. Serial No. 145,992.

This invention relates to improvements in sealing devices and the method of producing same. It relates particularly to seal ing devices for refrigerating machines wherein it is necessary to provide means for preventing the refrigerant from escaping through the openings through which shafts of the operating element pass, and to prevent air from entering the apparatus.

It is among the objects of the present invention toprovide a sealing device of simple structure and design, which may be produced easily and at minimum cost.

Further objects and advantages of the present invention will be apparent from the following description, reference beinghad to the accompanying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In refrigerating machines of the compressor-condenser-expander type the refrigerant, for example, sulphur dioxide is compressed in the pumping device,.liquefied in the condenser and evaporated in the expan-' sion apparatus, from which latter the refrigerant returns to the crank case of the compressor. Due to cycle surges in the operation of the system either a pressure or a vacuum may prevailin the crank case of the compressor. Consequently when a pressure pervails, there is danger of refrigerant leaking out through the bearings of the crankshaft, thus constituting a nuisance, while when a vacuum prevails, air may leak into the crank case and in mixing with the refrigerant, derange the proper functioning of the system. For this reason various means have been suggested for sealing such shafts.

Since-the shaft rotates, it is however difficult to produce an effective seal. By means .of the present invention a seal is provided which prevents the leakage of refrigerant from and the leakage of air into the compressor and in which the sealing facility increases with rising pressures.

In the drawing:

Fig. 1 illustrates the cylinder from which the sleeve of the sealing device is made;

Fig. 2 shows the cylinder provided with a flange, the result of the first step in the operation;

Fig. 3 shows the cylinder wall provided with corrugations which reduce the diameter of one end thereof;

Fig. 4 is a fragmentary view showing the sealing device in cross-section;

Fig. 5 is a cross-sectional View of one of the members of the sealing device; and

Fig. 6 is a section taken along line 66 of Fig. 5.

The results in the various steps in the method are clearly depicted in the Figs. 1, 2, 3 and 5 of the drawing. First a cylinder 20, preferably of metal, is provided, which, by rolling or swaging, is provided with a flange 21 at its one end as shown in Fig. 2. This flanged cylinder is then placed in a machine and corrugations comprising ridges 22 and grooves 23 are formed in the cylindrical wall, the corrugations gradually diminishing as they approach the flange 21, see Fig. 3. This reduces the diameter of the sleeve at the end opposite the flange 21, and gives it a frustro-conical shape, the side wall 24 tapering from the flange toward the opposite end.

The sleeve is now supported in a machine having a cutting or grinding tool of proper size and coaxially mounted relative to the sleeve. Directing the cutting or grinding tool through said sleeve removes portions of the corrugations whereby a cylindrical surface is provided within the smaller end thereof. As shown in Fig. 5, this cut or grind should be of a diameter so as to reach substantially the outer edges of the ridges of the corrugations, otherwise a continuous, cylindrical surface, capable of fitting snugly about a shaft to provide a seal would not be obtainable. Reference to Fig. 5 shows this surface to be of serpentine formation due to the angularity of the corrugated side wall 24. The corrugations render the side wall of the sleeve annularly contractible so that the pressure thereon can increase the pressure or grip of the sleeve about the shaft to insure the seal.

The drawing illustrates the sealing device attached to a shaft 30 journalled in the bearing 31 provided in the casing 32 of a compressor used in connection with refrigerating apparatus, not shown. The shaft 30 has a reduced portion 33 extending through a chamber 34 formed in the casing 32, coaxial with the shaft. A shoulder portion 35 is provided in the casing, said shoulder being spaced from the bearing 31 and defining the enlarged portion 36 of the chamber 34.

The sealing device, shown in the Fig. 4, comprises two of the sleeves as shown in F ig. 5, placed on the shaft so that their flanges 21 he adjacent each other. A washer 40 is placed between the said flanges. The smaller end of the right sleeve, numbered 41 fits snugly about the shaft portion 33 adjacent the bearing 31 or the enlarged portion 30 of the shaft, while the smaller end of the left sleeve 42 snugly fits about the shaft portion 33 adjacent its outer end. The shape of the sleeves 41 and 42, provides a space around the shaft portion 33 within said sleeves. This space is filled with a compound 44 adapted to assist in sealing the joint between said shaft portion and the smaller ends of the sleeves, and it also lubricates these joints.

When in proper position on the shaft the flange 21 of the sleeve 41 engages the shoulder portion 35, while the tapered or sloping wall 24 thereof extending into the chamber 34 provides a triangular shaped chambered portion in the said chamber 34, defined by the wall 24, casing 32 and shaft 31, this chambered portion being sealed by the joints between the flange 21 and shoulder 35 and the small end of the sleeve 41 and shaft portion 33.

The flange 21 is held hermetically against the shoulder 35 by the end surface of the annular flange 46 extending into the chamber 36, and engaging the flange 21 of the sleeve 42 which it tightly presses against the washer 40 interposed between the flanges of the two sleeve members 41 and 42. The flange 46 is formed on a plate 47 secured tothe casing 32 by means of studs 48. It is therefore apparent that the interior of the chamber 34 is divided into two compartments, one of which communicates with the interior of the crank case through the leakage which inevitably occurs through the bearings, while the other communicates with the atmosphere through the play between the shaft and the end wall or plate member 47.

When the pressure in the compressor increases and there is a leak at the bearing 31, the fluid entering the chamber 34 will exert a pressure upon the wall of the sleeve 41 tending annularly to contract the said sleeve thereby increasing the pressure thereof upon the shaft and thus assuring a tighter joint between these two members. The slope of the walls 24 of the sleeves permits a longer bearing surface to be provided at their ends as well as providing the space including the sealing and lubricating compound within the sealing device.

' The method disclosed reduces the production of a packing or seal to a minimum cost of materialand labor. The design permits replacement of parts with Very little trouble and expense.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is tobe understood that other forms might be adopted, all coming within the scope of the claim which follows.

What is claimed is as follows:

In a refrigerating system, a compressor a sealing device therefor comprising in com ination a casing having a bearing, a shaft journalled in said bearing, a chamber provided about the shaft adjacent said bearing, a sealing device surrounding said shaft and disposed in said chamber, said device comprising oppositely disposed and annularly contractible corrugated metal members having tapered portions, the outer ends of which are adapted to fit snugly about the shaft, the intermediate portions of said members being "secured to the casing so as to divide said chamber into two compartments, one of said compartments communicating with the atmosphere and the other with the interior of said casing, and a compound within said metal members adapted to seal the compartment communicating with the compressor from the atmosphere.

In testimony whereof I hereto aflix my signature.

FRANCIS E. STEVENSON. 

